package thread;
class Counter{
    public int count = 0;
    synchronized public void add(){
        count++;
    }
    public void add1(){
        synchronized (this){
        count++;
        }
    }
    //static方法没有this，
    //也叫做类方法，和具体实例无关
    synchronized public static void func(){

    }
    public static void func2(){
        synchronized (Counter.class){

        }
    }
}
public class Demo20 {
    public static void main(String[] args) throws InterruptedException {
        Counter counter = new Counter();
        Thread t1 = new Thread(()->{
            for (int i = 0; i < 50000; i++) {
                    counter.add();

            }
        });
        Thread t2 = new Thread(()->{
            for (int i = 0; i < 50000; i++) {
                    counter.add();

            }
        });
        t1.start();
        t2.start();
        t1.join();
        t2.join();
        System.out.println(counter.count);
    }
}
